1. Field of the Invention
The present invention relates to an input apparatus, and particularly to a resistive type input apparatus.
2. Description of the Related Art
In recent years and continuing, touch panel type input apparatuses are attracting much attention because of their good operability as input apparatuses of information processors. The touch panel type input apparatus is combined with a display apparatus, and since an input can be directly made towards a display shown on the display apparatus, an operation in coherence with the human senses can be realized. In such a touch panel type input apparatus, thinness and durability are in great demand.
[Configuration of the Conventional Input Apparatus]
FIG. 1 is a diagram showing an exemplary configuration of an input apparatus according to the conventional art.
A conventional input apparatus 1 includes a touch panel 11 and a control substrate 12. The touch panel 11 includes an upper substrate 21, a lower substrate 22, and a spacer 23 placed in between the two substrates 21 and 22.
The upper substrate 21 has a film substrate 31, a transparent conductive film 32 made of ITO (indium tin oxide), for example, that is formed on the film substrate 31, and low resistance conductive patterns 33 and 34 formed parallel to each other on the transparent conductive film 32 at the two edges of the transparent conductive film 32 with respect to directions Y (Y1 and Y2).
The lower substrate 22 has a glass substrate 41, a transparent conductive film 42 made of ITO, for example, that is formed on the film substrate 41, and low resistance conductive patterns 43 and 44 formed parallel to each other on the transparent conductive film 42 at the two edges of the transparent conductive film 42 with respect to directions X (X1 and X2).
The low resistance conductive patterns 33 and 34 of the upper substrate 21 are connected to low resistance conductive patterns 45 and 46 that are arranged on the lower substrate 22. The low resistance conductive patterns 45 and 46 are connected to the control substrate 12 via a flexible printed wiring board 61. The low resistance conductive patterns 43 and 44 formed on the lower substrate 22 are also connected to the control substrate 12 via the flexible printed wiring board 61.
[Coordinates Detection Operation]
In a coordinates detection operation, first, the control substrate 12 applies a driving voltage between the conductive patterns 33 and 34 formed on the upper substrate 21, and detects the electrical potential of either conductive patterns 43 or 44 formed on the lower substrate 22. In this way, a coordinate in the directions Y can be detected.
Next, the control substrate 12 applies a driving voltage between the conductive patterns 43 and 44 formed on the lower substrate 22, and detects the electrical potential of either conductive patterns 33 or 34 formed on the upper substrate 21. In this way, a coordinate in the directions X can be detected.
In the conventional input apparatus 1, the above operations are alternately performed to detect the x and y coordinates.
However, in the conventional input apparatus, the patterns are formed by printing silver onto the transparent conductive films on the glass substrate and the film substrate. Thereby, gradation and migration are generated and this prevents the realization of a thinner input apparatus.
Also, since in this type of input apparatus, the input operation is performed by deforming the film substrate, the film substrate or the transparent conductive film is easily damaged. Further, in the conventional input apparatus, the coordinates of the directions X are detected from the resistance value of the film substrate. Therefore, even the slightest damage such as a minor scratch on the film substrate or the transparent conductive film can be a detriment to the accurate detection of the coordinates. Thus, there is a need for improvement in the durability of the input apparatus.